| /* RemoteObjectInvocationHandler.java -- RMI stub replacement. |
| Copyright (C) 2005 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package java.rmi.server; |
| |
| import gnu.java.rmi.server.RMIHashes; |
| |
| import java.io.Serializable; |
| import java.lang.reflect.InvocationHandler; |
| import java.lang.reflect.Method; |
| import java.lang.reflect.Proxy; |
| import java.rmi.Remote; |
| import java.rmi.RemoteException; |
| import java.rmi.UnexpectedException; |
| import java.rmi.registry.Registry; |
| import java.rmi.server.RemoteObject; |
| import java.rmi.server.RemoteRef; |
| import java.rmi.server.UnicastRemoteObject; |
| import java.util.Hashtable; |
| |
| /** |
| * Together with dynamic proxy instance, this class replaces the generated RMI |
| * stub (*_Stub) classes that (following 1.5 specification) should be no longer |
| * required. It is unusual to use the instances of this class directly in the |
| * user program. Such instances are automatically created and returned by |
| * {@link Registry} or {@link UnicastRemoteObject} methods if the remote |
| * reference is known but the corresponding stub class is not accessible. |
| * |
| * @see Registry#lookup |
| * |
| * @author Audrius Meskauskas (AudriusA@Bioinformatics.org) |
| */ |
| public class RemoteObjectInvocationHandler extends RemoteObject implements |
| InvocationHandler, Remote, Serializable |
| { |
| /** |
| * Use the jdk 1.5 SUID for interoperability. |
| */ |
| static final long serialVersionUID = 2L; |
| |
| /** |
| * The RMI method hash codes, computed once as described in the section 8.3 |
| * of the Java Remote Method Invocation (RMI) Specification. |
| */ |
| static Hashtable methodHashCodes = new Hashtable(); |
| |
| /** |
| * The empty class array to define parameters of .hashCode and .toString. |
| */ |
| static final Class[] noArgsC = new Class[0]; |
| |
| /** |
| * The class array to define parameters of .equals |
| */ |
| static final Class[] anObjectC = new Class[] { Object.class }; |
| |
| /** |
| * The empty object array to replace null when no args are passed. |
| */ |
| static final Object[] noArgs = new Object[0]; |
| |
| /** |
| * Construct the remote invocation handler that forwards calls to the given |
| * remote object. |
| * |
| * @param reference the reference to the remote object where the method |
| * calls should be forwarded. |
| */ |
| public RemoteObjectInvocationHandler(RemoteRef reference) |
| { |
| super(reference); |
| } |
| |
| /** |
| * Invoke the remote method. When the known method is invoked on a created RMI |
| * stub proxy class, the call is delivered to this method and then transferred |
| * to the {@link RemoteRef#invoke(Remote, Method, Object[], long)} of the |
| * remote reference that was passed in constructor. The methods are handled as |
| * following: |
| * <ul> |
| * <li> The toString() method is delegated to the passed proxy instance.</li> |
| * <li>The .equals method only returns true if the passed object is an |
| * instance of proxy class and its invocation handler is equal to this |
| * invocation handles.</li> |
| * <li>The .hashCode returns the hashCode of this invocation handler (if the.</li> |
| * <li>All other methods are converted to remote calls and forwarded to the |
| * remote reference. </li> |
| * </ul> |
| * |
| * @param proxyInstance |
| * the instance of the proxy stub |
| * @param method |
| * the method being invoked |
| * @param parameters |
| * the method parameters |
| * @return the method return value, returned by RemoteRef.invoke |
| * @throws IllegalAccessException |
| * if the passed proxy instance does not implement Remote interface. |
| * @throws UnexpectedException |
| * if remote call throws some exception, not listed in the |
| * <code>throws</code> clause of the method being called. |
| * @throws Throwable |
| * that is thrown by remote call, if that exception is listend in |
| * the <code>throws</code> clause of the method being called. |
| */ |
| public Object invoke(Object proxyInstance, Method method, Object[] parameters) |
| throws Throwable |
| { |
| if (!(proxyInstance instanceof Remote)) |
| { |
| String name = proxyInstance == null ? "null" |
| : proxyInstance.getClass().getName(); |
| throw new IllegalAccessException(name + " does not implement " |
| + Remote.class.getName()); |
| } |
| |
| if (parameters == null) |
| parameters = noArgs; |
| |
| String name = method.getName(); |
| switch (name.charAt(0)) |
| { |
| case 'e': |
| if (parameters.length == 1 && name.equals("equals") |
| && method.getParameterTypes()[0].equals(Object.class)) |
| { |
| if (parameters[0] instanceof Proxy) |
| { |
| Object handler = Proxy.getInvocationHandler(parameters[0]); |
| if (handler == null) |
| return Boolean.FALSE; |
| else |
| return handler.equals(this) ? Boolean.TRUE : Boolean.FALSE; |
| } |
| else |
| return Boolean.FALSE; |
| } |
| break; |
| case 'h': |
| if (parameters.length == 0 && name.equals("hashCode")) |
| { |
| int hashC = Proxy.getInvocationHandler(proxyInstance).hashCode(); |
| return new Integer(hashC); |
| } |
| break; |
| case 't': |
| if (parameters.length == 0 && name.equals("toString")) |
| return "Proxy stub:"+ref.remoteToString(); |
| break; |
| default: |
| break; |
| } |
| |
| Long hash = (Long) methodHashCodes.get(method); |
| if (hash == null) |
| { |
| hash = new Long(RMIHashes.getMethodHash(method)); |
| methodHashCodes.put(method, hash); |
| } |
| |
| try |
| { |
| return getRef().invoke((Remote) proxyInstance, method, parameters, |
| hash.longValue()); |
| } |
| catch (RuntimeException exception) |
| { |
| // RuntimeException is always supported. |
| throw exception; |
| } |
| catch (RemoteException exception) |
| { |
| // All remote methods can throw RemoteException. |
| throw exception; |
| } |
| catch (Error exception) |
| { |
| throw exception; |
| } |
| catch (Exception exception) |
| { |
| Class[] exceptions = method.getExceptionTypes(); |
| Class exceptionClass = exception.getClass(); |
| |
| for (int i = 0; i < exceptions.length; i++) |
| { |
| if (exceptions[i].equals(exceptionClass)) |
| throw exception; |
| } |
| throw new UnexpectedException(method.getName(), exception); |
| } |
| } |
| |
| } |